


A Mutually Beneficial Agreement

by Saebrin



Series: Mutual Benefits [1]
Category: Harry Potter - J. K. Rowling
Genre: Book 3: Harry Potter and the Prisoner of Azkaban, Implied/Referenced Child Abuse, M/M, Pre-Slash
Language: English
Status: Completed
Published: 2017-09-24
Updated: 2017-09-24
Packaged: 2019-01-04 19:24:50
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,623
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12175128
Author URL: https://archiveofourown.org/users/Saebrin/pseuds/Saebrin
Summary: What do you do when you want something, and only your enemy can give it to you? (AKA that time Marcus Flint learned to cast a Patronus, and Harry got split custody of a cat.) Set during Prisoner of Azkaban.





	A Mutually Beneficial Agreement

**Author's Note:**

> Technically, bits of this don’t match the timeline from POA. Let’s just pretend Sirius invading the dormitory to find Pettigrew happened a month or two later than in the book, yeah?

_Shh-chh._  

Harry froze mid-corridor, his heart hammering as he clutched the Invisibility Cloak tighter ’round himself.

_Shh-chh._

There it was again. A stealthy sound, softness whispering against stone.

He strained his ears but noticed nothing more on the chilly midnight air. Still, the hairs on his neck prickled. In his three years at Hogwarts, he’d encountered great bloody snakes in the plumbing, and slavering Cerberus dogs, and trolls on the loose… What could top those? Nothing, he hoped, but maybe Fate was choosing now to disillusion him. Maybe he was due for a round of complacency killing.

… Or maybe it was just a rat.

He peered into the gloom ahead, and when that bore nothing, behind, at the suits of armor and slumbering paintings, the classroom doors standing closed and locked, the trio of frosted windows that stared out over the lawn. The Cloak lent a filmy greyness to everything, like looking through an oft-washed shirt that’d gone transparent.

Two more steps, and then _chhh!_ A clinking this time, the sound of fingernails on metal.

He spun back ’round, and there she was, Mrs. Norris slinking out from behind a suit of armor. He sucked in a startled breath, and every muscle seized in sync. Had she heard him?

Yes, it seemed.

The cat beelined straight to him as if the Invisibility Cloak were a cheap, malfunctioning party trick. He waited with a burgeoning sense of dread, mind already darting ahead to how many hours it’d take to polish up the trophy room.

But then the quiet registered. Oughtn’t Filch be shuffling ’round the corner by now, brandishing his lantern and hollering about students out of bed?

The cat crept closer, nosed at his trainers, and let loose a plaintive meow. Torchlight revealed long, exceedingly fluffy grey fur, along with eyes near as green as his own. Not Mrs. Norris after all. Relief flushed through him, sweet in his veins, an antidote to fear-poisoning.

“Hullo there, kitty,” he said in a hushed voice, and knelt to stroke its back and shoulders. His fingers snagged on the band of a collar. Leather, by the feel of it, with fine, delicate stitching. A purr started beneath his hand, low and rumbling.

Footsteps broke the quiet only moments later, echoing from the nearest set of stairs. Filch, perhaps, or prefects on patrol. Either way, he wasn’t sticking ’round to find out. Straightening with reluctance, he whispered goodbye.

He retreated, feeling that luminous stare on his back all the while.

 

* * *

 

“Messrs. Malfoy, Crabbe, and Goyle, see me after class,” Professor McGonagall ordered briskly a few days later, as most of the class stowed their textbooks and stampeded out the door, anticipating dinner. “You too, Potter.”

Ron and Hermione shot him curious, slightly worried looks as they packed up. “What’s going on, mate?” Ron whispered, and Harry could only shake his head.

“No idea,” he muttered back, tucking his notes into his bookbag.

The Slytherins crowded up to McGonagall’s desk, their expressions sour, and Harry eyed all three with suspicion as he did the same.

“You might as well stay standing,” the professor told them. “It’ll just be a moment.”

_A moment for what?_

Less than a minute later, his question was answered. The door creaked open to admit a burly figure with dark hair. Dear Merlin, it was _Flint_ , looking every bit as fierce as he tended to on the pitch. He strode up to the professor’s desk, a disgruntled frown curving his mouth, and said, “Let’s get this over with.” He, at least, appeared to know what they were here for.

Professor McGonagall surveyed the lot of them, her lips thin and eyes stern. “I believe you four owe Mr. Potter an apology for that awful spectacle at yesterday’s match. Dressing up as _Dementors,_ for Merlin’s sake! The usual tricks are one thing, but to sabotage a match between other teams… In all my years, I’ve rarely seen such a blatant lack of sportsmanship.”

Harry stared in disbelief. _She’s making them apologize? All the horrible things that’ve happened in this school, and this is where she draws the line?_ Well, she always had been very passionate when it came to Quidditch—he could attest to that, he thought, recalling how she’d waived the rule against first years playing on their house teams for him.

A drawn-out silence filled the room. Apparently, no one wanted to go first.

McGonagall’s expression darkened further still. “Ten points from Slytherin for a stunning show of pigheadedness,” she said curtly.

That seemed to spur Malfoy into action. “ _Sorry_ , Potter,” he said with a sneer. It was, without a doubt, the most venomous apology Harry’d ever received. “Am I excused?”

The professor’s lips twisted, but she nodded, resignation apparent; she’d not be coercing anything more genuine out of him. Malfoy stomped from the room, and Crabbe and Goyle, after each grunting their own apologies, hurried behind.

That left Flint, hip leaned against a desk in the front row, arms folded over his very, _very_ broad chest.

Those dark grey eyes regarded Harry stonily. Then, in a gruff voice, he forced out, “Sorry.”

“I’d suggest expanding on that a bit, Mr. Flint,” the professor said, lifting an eyebrow. “A certain amount of petty mischief can be expected from thirteen-year-olds. You, however, are an adult in the eyes of wizarding law, and one would hope that such frivolities would be a thing of the past.”

Flint stiffened noticeably at her words. The desk he was leaning on creaked as his knuckles whitened against the wood, but he didn’t let his temper get away from him. Instead, he turned to Harry and met his eyes. Through gritted teeth, he said, “I’m sorry, Potter. I made a mistake, and I should’ve known better.”

Harry thought he detected a very faint _than to listen to those bloody idiots_ under his breath, but decided not to point it out.

“That will do, Mr. Flint,” McGonagall said, and Flint was up and gone immediately.

 

* * *

 

On Thursday, that diabolical mistress Fate struck again—this time with much bigger ramifications. At least her location of choice was decently lit: a sun-flooded corridor on the fifth floor, near a windowed nook where the castle’s cats liked to lie and soak up rays.

Harry was coming back from the library when it happened.

“You again?” he asked as the fluffy grey cat wound between his ankles, rubbing strands of fur all over his trousers and school robes. He knelt to scratch beneath its chin, and it made a throaty sound and butted its head against his palm. “Who do you belong to?”

The _meow_ in response was hardly enlightening.

The cat rolled over, going belly-up, and unable to hold back a smile, Harry scritched the bared stomach with gentle fingers. The fur under his hand was soft, and he found the rumbling purr soothing. A small pang ran through him because as much as he loved Hedwig, you couldn’t exactly cuddle an owl.

In his peripheral, a tall figure rounded the corner. “Where’d you run off to, you barmy little— Potter? What the fuck are you doing to my cat?”

Shit. Oh, bloody hell. Why, of all people, did it have to be _Flint’s_?

He stilled his fingers mid-skritch, mouth working soundlessly, and tried to catch up with the galloping panic that set his pulse ajag.

Flint stormed closer, and closer still, ’til they were a scant few centimeters apart, his breath ghosting hot against Harry’s forehead. He loomed, jaw set and eyes narrowed accusingly. Involuntarily, Harry’s gaze dropped to his hands, which had balled into fists.

“I asked a question, you little prick.”

“I’m petting it,” was all he could think to say.

Flint glanced down at the cat, who was purring and arching under Harry’s palm, none the worse for wear. His brow eased from its angry furrow and his shoulders seemed to drop a bit, though his eyes remained narrow.

Might as well hazard a question, Harry decided. The worst Flint could do was kill him, right? And Harry’d not been impressed with anyone’s track record for accomplishing that.

“What’s he called?”

Flint snorted. “‘Traitor’ by the looks of it.”

Harry rolled his eyes, feeling a surge of confidence now that the glowering had subsided. “Come off it. He’s just being friendly.”

The quiet took on a stiff, awkward edge, as though Flint wasn’t sure how to reply.

Finally, though— “Maximus.”

“What?”

“His name. It’s Maximus.” Flint cleared his throat and hooked a finger into the knot of his tie, loosening it. The green and silver stood out against his tanned throat. “How’d you do it, anyway?”

Confusion shot through him. “Do what?”

“The Patronus. On the pitch.”

By some miracle, Harry refrained from clarifying, _The one that knocked you on your cheating arse?_ “I just thought of something happy. That’s what you’re supposed to do.”

Flint heaved a sigh. “I bloody _know that_. I mean how did you make it corporeal? All I get’s mist.”

“Oh.” Harry’s thoughts stumbled. Big, hulking seventh-year Marcus Flint wanted his _help_? And with a spell, of all things? “I had the same problem at first. You’ve got to keep at it for a while; Professor Lupin made me practice it loads of times.”

Flint scowled. “Well, great. Thanks for nothing, Potter.”

“I could help,” he blurted, before his brain caught up with his mouth and declared, _What a rubbish idea, Harry_.

Flint raised a thick, skeptical eyebrow. “How so?”

“My boggart. It’s a Dementor.”

“And?”

“You could practice on it. There’s one in Professor Lupin’s office. I reckon he’d let us use the classroom.”

Flint eyed him, head cocked in a manner that suggested half speculation, half suspicion. “What do you want in exchange?”

Of course. Slytherins didn’t do favors, did they? They were the tit-for-tat sorts; after all, a favor owed could rear up to bite when least anticipated.

After a pause for deliberation, Harry said, “Maximus.”

Flint’s expression morphed into one of outrage. Harry hastened to add, “I want you to let him visit me.”

Flint hesitated, probably caught wrong-footed by the simplicity of the demand, along with a titch relieved that Harry wasn’t _actually_ trying to nick his cat. Then he nodded, quick and jerky. “Done.”

For a moment it seemed as though they’d shake on it, but Flint just nodded again, stiff-jawed, and scooped Maximus off the floor before stalking away. Harry waited ’til the echo of steps on the staircase faded. Then he set off toward the Common Room, already cursing himself for an idiot.

(Later that night, Maximus meowed at the portrait hole ’til he was admitted by a sleepy-eyed second year, and then he trotted up the boys’ staircase and commandeered Harry’s pillow. He looked terribly smug as he kneaded it with his paws, a low, rocky rumble issuing from deep in his chest. If there were such a thing as smoker’s purr, Maximus had it.

Though guilt flooded him at the thought, Harry was relieved that Scabbers had gone missing the previous week at the hands—err, paws—of Crookshanks. He’d have felt awful if Maximus opted for a midnight snack, and he’d seen the deep rift Scabbers’s loss drove between Ron and Hermione. He’d quite like to avoid that with his best friend, thanks.

Guilt aside, he found the warmth and comfort of having company rather soothing. Was it worth spending time, voluntarily at that, with Flint?

Yes, he decided. Yes, it was.)

 

* * *

 

 _Session One_  

 

The next night, he rethought that assessment as their faux Dementor towered up from Professor Lupin’s trunk, robes a-billow, already leaching warmth from the room. A shudder racked his body. On his left, he was dimly aware of Maximus leaping off a desk and hissing, fur puffed to twice the usual size, before streaking out the door. On his right, Flint’s wand swept up, and a spatter of silver-grey sparks shot out, then died.

“Shit, shit— Potter!”

The panic lacing Flint’s voice jolted him into action. “Expecto patronum!”

The stag burst forth, snorting and tossing its head, and forced the boggart back until Harry could slam the trunk lid. He sat abruptly, shaky-limbed, pulse thundering like a Weird Sisters bassline. A glowing muzzle brushed his shoulder, and he looked up as the stag dissolved before him, leaving a quieter, dimmer room in its wake.

He met Flint’s wide grey gaze and said, “Give me a minute. We’ll try again.”

They did. And then again, and again after that. Flint never managed more than sparks.

 

* * *

 

 _Session Two_  

 

Right after they’d stepped into the classroom, Flint pulled a chocolate bar from his pocket and thrust it at Harry’s face. “Here,” he muttered.

Harry accepted the bar, which gave a bit under his fingers, squashed and softened by body heat. “Thanks.”

Flint grunted and ducked his head. “Whatever.” Brandishing his wand, he said gruffly, “Let’s get this over with.”

Several failed attempts passed, and then Harry asked in a moment of frustration, “Why d’you even want to learn this?”

Flint stayed quiet for a long moment, his expression stormy. Was he just going to pretend Harry hadn’t spoken? Maybe he’d overstepped some invisible line— _Thou shalt not ask personal questions_.

“Never mind,” he said, and moved forward to release the boggart again.

As he reached for the trunk latch, Flint blurted, “My Charms NEWT.” His gaze was firmly on his feet, and his hand clenched convulsively around the handle of his wand.

Harry paused with his palm against the lid, waiting for Flint to expand on that a bit.

“I’m … not so good at the writing part of it all,” Flint admitted after a pause. “So long as I do fine on the practical, though, I’ll pass. I need a Patronus to help my score.”

“Oh,” Harry said, and left it at that.

Later, though, as they were wrapping up for the night, he snapped the chocolate bar in two and gave half to Flint. Couldn’t let a _Slytherin_ one-up him in generosity, he told himself as he watched Flint lick a smudge of melted chocolate from his fingers.

 

* * *

 

 _Session Three_  

 

The next session was a disaster, ending prematurely when the boggart popped out of the trunk and noticed Flint instead of Harry.

In a blink it’d transformed into a tall, hulking man who bore a shocking resemblance to Flint, though quite a bit older—the same black hair, the same blunt jaw and broad face. Fresh blood dotted the man’s finely tailored robes. His teeth were bared in a snarl as he stalked forward, fists raised for a blow, advancing on a second, much smaller figure huddled on the floor.

Flint, who’d gone pale under his tan, barked, “Riddikulus!”

The man sank abruptly to his hands and knees. He neighed, loudly, and the second figure, which turned out to be a small boy, scrambled onto the man’s back. “Horsey rides! Horsey rides!” the boy shouted with a bright smile.

As the man crawled about on the floor, letting the child tug his hair as if pulling imaginary reins, Harry herded the pair toward the trunk. He hefted the lid shut once the boggart was inside.

The classroom door slammed while he still had his back turned.

 _Was that his father?_ Harry wondered, his mind whirring as he stood alone in the sudden quiet. _Or him_ becoming _his father?_

Flint didn’t return that evening, and Harry didn’t blame him.

 

* * *

 

 _Sessions Four - Eight_  

 

They tried a few more times over the next weeks, never progressing beyond a moderate fog. After the third failure one night, Harry threw up his hands. “What are you thinking of? Maybe you need a happier memory.”

Flint skinned his lips back in a snarl, revealing the oddly sharp teeth Harry had always found unsettling. They made him look a bit wolfish. “My memory is _fine_.”

“Well, there’s your problem.”

“Huh?”

“You said it’s fine. Fine isn’t enough. Not for this. It needs to be something really strong, really important. You have to feel it, not just think it.”

Flint faltered, gaze flickering to the side. “I don’t… What if there’s nothing strong enough?”

“There is, trust me. It took a while to figure mine out too.”

Flint bit his lip and crossed his arms. “What do you think of?”

Harry hesitated. Part of him balked at the idea of explaining—a pureblood like Flint wouldn’t understand. But no, if he was going to help, then honesty was the best route. “There are a few I use, but the first one that really worked was finding out I was a wizard.”

Flint shot him a bewildered look. “How could you not know?”

“I was raised by muggles, and they hate our kind,” he admitted, bitterness sweeping through him at the reminder of the Dursleys. “I didn’t even know magic existed ’til I was eleven.”

“You’re serious, aren’t you? Bloody ironic, that. Biggest celebrity in our world, and you thought you were a _muggle_.” Flint shook his head, looking incredulous.

The conversation was creeping into uncomfortable territory for Harry—he really didn’t want to hear Flint’s opinions on muggles, as they were probably more in line with Malfoy’s than his own—so he decided to steer it back on track. “Yeah. So, happy memories. Have you got a really strong one?”

They stood a while, silent, as Flint sifted through his mental catalogue. After what seemed an eternity, although a discreet _tempus_ purported it to be only five minutes, Flint straightened from his slouch and nodded decisively. “I want to try again.”

They assumed the now-familiar positions. When the boggart rose from the trunk, bringing with it that insidious chill, and the usual mist coughed from the tip of Flint’s wand, Harry couldn’t help but feel a flash of disappointment.

It was brief, though.

Flint let out a rather feral growl, and suddenly the mist was flowing together, melding, brightening. Four hooved legs formed first, then the solid bulk of a body, and finally a short neck that extended into a snout and the pièce de résistance: a pair of thick, spiraling horns.

The ram charged forward and head-butted the boggart, sending it staggering back into the trunk. Harry lunged to shut the lid, and when he turned back around, still panting for air, the broad grin lighting Flint’s face was infectious.

“Bleedin’ brilliant,” Flint crowed, bouncing on the balls of his feet. He looked childishly gleeful, as if he’d just won the Quidditch Cup. The ram trotted back to him, silvery body gleaming, and it bowed its head before fading. Even after it had gone, Flint stared at the empty air. His smile made him seem younger, frown lines smoothing out, dimples—honest-to-Merlin _dimples_ —appearing at the edges of his mouth.

 _What did you think of?_ Harry wanted to ask, but he had a feeling it’d be too intimate a question.

They tried the charm again, with the same success, and then a third time to ensure it was no fluke. Finally, Harry locked the trunk and sank back against a nearby desk. “I think you’ve got it now.”

“I do, don’t I?” Flint said with a grin. He composed himself after a moment, tamping down on his excitement, but it still shone through in his eyes. As he stepped forward and clapped a hand against Harry’s shoulder, his mouth twisted into a small, crooked smile.

“Thanks, Potter, for your help.”

Flint started toward the door. At the threshold he paused to add, “Don’t think I won’t crush you on the pitch, though. You’ve not earned _that_ much good will.”

“Wouldn’t dream of it,” Harry said before Flint walked away.

 

* * *

 

Even after the Patronus lessons ended, the visits from Maximus carried on. At least two or three nights a week, Harry would find the cat hopping into bed and hogging his pillow. 

And after the nightmarish events with the Shrieking Shack and the Time-Turner rescue, after OWLs and NEWTs concluded, after the Leaving Feast and the train home and three very uncomfortable weeks with the Dursleys, as he lay in bed one night, listening to the rain—

There was a _tap-tap-tap_ at his window.

He opened it, and a huge barn owl swept inside. It settled on Hedwig’s perch, where it shook the rain from its wings.

The parchment he untied from its leg held only a few lines, in spiky script:

_I FUCKING PASSED! Got me an A. Fucking right, Potter. You’re not half-bad for a Gryffindork. If you’re ever in Falmouth, owl me—Max and I’ll buy you a beer._

Taped below that was a picture of Maximus. He lay sprawled in a sunbeam on what looked to be a window seat, tail swishing and eyes skinnied down to contented slits. Occasionally, a hand—huge, broad, and dotted with scars—appeared from out of the shot to stroke his back.

With a smile, Harry padded to his trunk and rooted out the photo album Hagrid had given him at the end of first year. He flipped through until he found an empty slot, and then tucked the picture and the note in next to a photo of his mum and dad painting his nursery. As he watched, his dad reached out with messy hands and blotted paint on his mum’s nose. She gasped and then, face alight with laughter, she retaliated with a flock of dripping, dive-bombing paintbrushes. He’d seen this moment countless times over the last two years, but it still made him smile, even as a wave of melancholy washed through him.

Like so many others from his past, Flint and Maximus were gone now. _Unlike_ the others, though, it didn’t have to be permanent.

Maybe, just maybe, he’d take Flint up on that beer.


End file.
